Hi everyone. I've got an 86 Fiero GT. Supposedly it was just sitting there for 15 years. I have it running now, but currently have slave cylinder issues, high idle, and slight overheating. I've already started a thread on the slave cylinder problem and have seen tons of advice on the high idle. Vacuum leaks is a big problem that causes high idle, mines around 2200 to 2600 RPM. I found a leak by the EGR and stopped that, but it sounds like there is still a leak somewhere and I've sprayed lots of carb cleaner to find it but I can't find it. My speed control, which is not working, has two vacuum hose receptacles with nothing on them (picture below). I figure if I find the vacuum source for this, I will find the leak, or so I hope. As for the overheating, I've tried to purge the air out of the cooling system but have no luck as the engine is idling so high more coolant comes out than I'm able to put in. So once I correct the high idle, I should be able to correct the slight overheating. Thanks ahead to all.

Cut a strip of aluminum can the width of the UPC. Take off the dist cap and lay it aside. Don't remove the wires except for the one or two you need to put it aside. Take a 10mm wrench and loosen the two bolts that hold the EGR tube to the bottom of the intake snout. Slip the aluminum between the EGR tube and the bottom of the intake. Tighten the two bolts, replace the dist cap and reattach the two wires. See if your idle problem is solved. If so there is a crack under the insulation. It is very hard to find that leak with the insulation in place. 80% of high idle problems on the V6 are from that tube being cracked. You can replace the tube or braze or have it brazed back together.

Leaving the aluminun strip in place is not a good long term solution. The computer advances the timing when it activates the EGR. This can cause pre-ignition and can destroy your pistons. If you chose to eliminate the EGR, and EGR tube and EGR control solenoid, you must also have it programmed out of the ECM. You can purchase a PROM for your ECM that has the EGR programmed out here - http://www.reddevilriver.com/Related_Products.html - note - shameless self promotion

---
Vacuum lines


"extra' vacuum fitting at the cruise
https://www.fiero.nl/cgi-bin...7645&style=printable

Note - the electro-vacuum cruise on the Fiero sucks.

Digital GM cruise
http://www.fieros.de/en/articles/digcruise.html

[This message has been edited by phonedawgz (edited 11-24-2014).]

Also look at phondawgz's diagram showing the brown and red vacuum lines going to the throttle body. If his suggestion doesn't indicate the cause and the intake or throttle body has ever been removed those may not have been reattached well. There's also a larger short line at the back of the throttle body that sometimes loses it's seal when the throttle body is removed. It's located directly behind where my pen is pointing. The two vacuum line ports can be seen on either side of the pen.

Thanks phonedawgz and fierofool. I'm going to do all that that you both suggested. Thanks to fierofool I now know that the two hose receptacles on the cruise control do not have anything connected to them. So there is no vacuum source unplugged. I do have a new IAC and a new MAT sensor that I got from the Fiero store. I will try phonedawgs method first and look at fierofools suggested possible vacuum leaks before installing these new parts.If I find the problem before installing them, I'll just keep them for later use

Plug the port on the trunk wall vacuum line that is attached to the C/C vacuum canister. It is not uncommon for the vacuum hose to the canister to be cracked or a rust hole in the canister.

If you do install the new IAC, inspect it before adjusting it. Your instructions may tell you that the adjustment should be 1 1/8 inch from the top of the pintel to the flanged seat where the gasket sits. There are two styles of IAC's. One has a slot on either side of the pintel shaft. This style should be adjusted by exerting inward force on the end of the pintel while rocking it from side to side. It will slowly move inward. If you rotate it you will damage it.

The other style has a smooth round shaft. To adjust this one, hold the IAC in your hand and with your thumb and finger, retract the spring away from the two notches in the pintel. Now you can screw it downward to achieve the required setting.

You can even make the measurement a little under 1 1/8 inch just to prevent jamming it and damaging it. It will adjust itself.